1. Field of the Invention
The present invention is directed to a housing for an electronic circuit for a fuel pump, composed of a printed circuit board, electric and/or electronic components which are arranged on the printed circuit board, a base and a cover which is connected to the base, wherein the base and the cover form the housing.
2. Description of the Related Art
An electronic circuit is used in fuel pumps of motor vehicles in order to feed fuel from a fuel container to an internal combustion engine. The electronic circuit is required to operate the electronically regulated electric motor of the fuel pump. The printed circuit board used here generally is composed of a fiber-reinforced plastic, such as an epoxide, a duroplast a thermoplast, or PTFE. The fiber material used may include a glass fiber, a plastic fiber, a carbon fiber, a plant fiber or paper. Owing to the arrangement of the electronic circuit in the fuel pump or in the immediate surroundings thereof, the electronic components and printed circuit boards have to be protected against the aggressive substances contained in the fuel. Since fuel components also diffuse through printed circuit boards, they do not offer sufficient protection. For this reason, in order to protect the electronic circuit the printed circuit board is arranged with the components inside a sealed metal housing. The feedthroughs for the electronic connections have to be embodied as glass/metal feedthroughs. The disadvantage of these glass/metal feedthroughs is the complexity and the cost involved in manufacturing the seal.
It is also known to arrange components on a ceramic base and to solder the ceramic base to a metal cover, with the result that the components are arranged and protected between the ceramic base and the cover. The ceramic base acts here as a diffusion barrier for the fuel.
A disadvantage in the two embodiments is the considerable cost factor of such housings, which cost factor permits economic use only for high-value applications.